Condoms missing...

Found two condoms missing from mine and my husband's "Stash" that we use when we want to be intimate for "LONG PERIODS" anyways...so I meet him at his car today and ask him why they are missing...his excuse: "I Masterbated with them. I'm actually pissed you would assume I cheated on you!" they've been missing as of a week ago...
Do I believe him?

Ya, that's a little hard. The fact he had to overly clarify and clear himself of wrong doing sends me a red flag. My ex used the excuse that he "let his buddy have 2 because he was feeling this new girl, and wanted to be covered just in case."

I asked my husband just to get his perspective and he said he knew a single guy in college (so he had no reason to lie) that said that he did because of the mess. Hubby thinks its ridiculous and he said any other time he's heard someone say it, it was in conjunction with their SO finding something so he never believed it. So, IDK I guess it could go either way. :?

OP the fact that he turned it around on you by saying that he couldn't believe you thought he was cheating is a big red flag.
Typically when somebody is being unfaithful they try to make the other person feel guilty.